1. Field of the Invention
This invention relates to a novel and useful phosphine sulfide represented by formula (1) and a manufacturing process therefor.
This invention also relates to a process for manufacturing a poly(alkylene oxide) by polymerizing an alkylene oxide in the presence of the phosphine sulfide.
A poly(alkylene oxide) is an important polymer, for example, as a starting material for a polyurethane foam or elastomer by reacting it with an isocyanate or as a surfactant.
This invention also relates to a process for manufacturing a 1,2-dioxyethane derivative by reacting an epoxy compound with a carboxylate, carboxylic anhydride, carbonate or phenol compound in the presence of the phosphine sulfide. Such a 1,2-dioxyethane derivative is a very important compound as an intermediate for a pesticide or medical drug or a starting compound for a polymer material.
2. Description of the Related Art
Hydroxides or carbonates of alkali or alkaline earth metals have been used as a catalyst or reagent for a variety of reactions because of their basicity. These are, however, water-soluble while generally insoluble in an organic solvent, and are, therefore, little applicable to a reaction in an organic solvent. Thus, there have been disclosed a variety of highly basic organic compounds such as 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo(4.3.0)-5-nonene and 1,4-diazabicyclo[2.2.2]octane.
Their basicity or catalytic action based on their basicity are, however, limited. Recently, there have been found organic compounds designated as a phosphazene base consisting of carbon, hydrogen, nitrogen and phosphorous atoms which are strong bases having strong hydrogen-withdrawing ability (Nachr.Chem.Tech.Lab., 38, 1214-1226 (1990)).
It has been described that a phosphazene base may act as an effective catalyst for anionic polymerization of ethylene oxide using an alcohol as an initiator (Martin Moller et al., Macromol.Rapid Commun., 17, 143-148 (1996)).
A complicated process should be employed for preparing a phosphazene base, and in the process, a stronger base such as potassium amide should be used for making the phosphazene base strongly basic(Nachr.Chem.Tech.Lab., 38, 1216 (1990)). Preparation of a phosphazene base is, therefore, not industrially advantageous. In addition, the base has a problem in handling that it is susceptible to deterioration by carbon dioxide in the air due to its strong basicity.
Tris[tris(dimethylamino)phosphoranylideneamino] phosphine oxide is also known as a useful base (G. N. Koidan et al., Journal of General Chemistry of the USSR, 55, 1453 (1985)). The phosphine oxide is, however, extremely hygroscopic; for example, it may absorb moisture to 7 to 8 wt % after storing in an ordinary atmosphere (temperature: 18 to 24.degree. C.; humidity: 52 to 59%) for 24 hours. Its solubility in water is 50 wt % or higher. Due to its higher hygroscopicity, the phosphine oxide can be used in limited applications as a catalyst and requires special precautions in handling for ensuring stable catalytic action.
For preparing a poly(alkylene oxide) by polymerization of an alkylene oxide, it is common to form an alkali-metal salt of an active hydrogen compound from an active hydrogen compound such as a polyhydric alcohol and a basic alkali-metal compound such as potassium hydroxide, by dehydration before initiation of polymerization. The process has been industrially put to practical use.
Initiator systems of other combinations have been disclosed. For example, U.S. Pat. No. 3,829,505 has disclosed preparation of a polymer of propylene oxide using a compound represented by Zn.sub.3 [Fe(CN).sub.6 ].sub.2.H.sub.2 O.dioxane as an active hydrogen compound. JP-A 2-276821 has disclosed preparation of a polymer by reacting a polyol prepared using zinc-hexacyanocobaltate complex with sodium methoxide and then with ethylene oxide. JP-A 62-232433 has disclosed preparation of a polymer by polymerizing ethylene oxide using a product which is prepared by adding a solution of diethylzinc in hexane to a dispersion of 1,4-butanediol and a nonionic surfactant in a slurry of fumed silica in hexane. Any of these, however, comprises a metal component. If there remains the metal component in a poly(alkylene oxide) product, it may adversely affect a reaction during preparation of polyurethane or the physical properties of polyurethane. Thus, a special procedure or complicated process is required for adequately removing the metal component in preparing the poly(alkylene oxide).
On the other hand, JP-A 50-159595 has disclosed preparation of a polymer from ethylene oxide, using an initiator system which is a combination of an alkanepolyol as an active hydrogen compound and boron trifluoride-etherate. It is, however, known for the initiator system that a specific impurity in the polymer may adversely affect physical properties of polyurethane and thus a complicated process is required to adequately remove it. JP-A 57-12026 has disclosed preparation of a polymer of an alkylene oxide using an alcohol and aminophenol. JP-A 56-38323 has disclosed polymerization of propylene oxide using sorbitol and tetramethylammonium hydroxide. These systems, however, have problems such as insufficient polymerization activity and residual amine odor.
A process for preparing a poly(alkylene oxide) is known, in which an alkylene oxide is polymerized in the presence of a phosphazene base and an active hydrogen compound (EP 0763555; Macromol.Rapid Commun., Vol.17, pp.143-148 (1996); Macromol.Symp., Vol.107, pp.331-340 (1996)). The phosphazene base in the process is an initiator having a strong basicity. A complicated process should be, however, employed for preparing the phosphazene base, and in the process, a stronger base such as potassium amide should be used for making the phosphazene base strongly basic. Preparation of a phosphazene base is, therefore, not industrially advantageous. In addition, the base has a problem in handling that it is susceptible to deterioration by carbon dioxide in the air due to its strong basicity.
EP 0791600 has disclosed a process for preparing a poly(alkylene oxide) by polymerizing an alkylene oxide in the presence of substantially a phosphazenium salt of an active hydrogen compound. In this process, prior to initiating polymerization, the phosphazenium salt of the active hydrogen compound should be prepared by, for example, dehydration as in the process using an active hydrogen compound and an alkali-metal hydroxide as an initiation system, or desalting, which requires an additional equipment. Furthermore, inorganic salts formed during the step may interfere with successful proceeding of the polymerization, and therefore, the salts should be removed, making the process more complicated. Thus, the process should be industrially improved.
It is known that for example tertiary amines, quaternary ammonium salts and quaternary phosphonium salts may enhance a reaction of an epoxy compound with a carboxylate, carboxylic anhydride or carbonate to prepare a 1,2-dioxyethane derivative (K.Funabashi, Bulletin Chemical Society of Japan, vol.52, p.1488 (1979); Tadaomi Nishikubo, Yuki Gosei Kyokai Shi, vol.49 (3), p.219 (1991)). However, such a catalyst as the tertiary amines, quaternary ammonium salts and quaternary phosphonium salts exhibits inadequate activity. The catalyst may be used in an increased amount or concentration or the reaction may be conducted under severe conditions, to adequately proceed the reaction, but such a manipulation may cause problems such as side reactions and decomposition of a reactant or product, and an yield or selectivity is inadequate.
It is also known that an acid such as boron trifluoride or a base such as a tertiary amine and a tertiary phosphine may accelerate a reaction of an epoxy compound and a phenol compound to prepare a 1,2-dioxyethane derivative. These conventional acid or base catalysts, however, have inadequate catalytic activity.